How frequently do flow meters need to be calibrated?
Electromagnetic sensors have excellent repeatability and hold their calibration for extended periods of time. We recommend annual calibration.
Why do TSI Flowmeters use electromagnetic sensor technology in their fire service flow meters?
Electromagnetic flow meter sensors have no mechanical moving parts in the water stream, thereby making it a very robust sensing technology. There are no moving parts that can be damaged by stones, plastic or other debris in the water stream.
“Having tried various types of hydrant test meter, We now exclusively use TSI portable flow meters for our hydrant test technicians. We know we can rely on the meter to work and for the meter not to become damaged by debris in the water.”
David Smith, Managing Director, Larsen Water Management
How do electromagnetic flow meters work?
The water flow meter used in all TSI Flowmeters Ltd products is an electromagnetic type. Its principle of operation is
as follows. Magnetic coils are placed at the top and bottom of the pipe setting up a magnetic field that is perpendicular
to the direction of flow of the water. Water is conductive and the flowing water breaking the magnetic field generates a
small electromotive voltage, perpendicular to the axis of the magnetic field and the flowing water.
Please refer to the figure below:
If the flow velocity is V [cm/s], the magnetic flux density is B [Gauss], and the pipe diameter is D [cm] then the induced
electromotive voltage, E, will be E = BVD * 10-8 [volts]. The induced voltage is directly proportional to the flow velocity as long as the pipe diameter and the magnetic flux are constant. Therefore, by measuring the electromotive voltage, we can measure the flow rate of the water.
After Sales Support?
Product manuals and software are available for download from the downloads section.
How to use video can be viewed in the videos section.
If you need further assistance or advice please Contact Us.
My new fire appliance has flow meters. Can you advise how to use the flow meters?
How to use video can be viewed in the appliance videos section.
Why is accuracy of flow measurement important?
Modern firefighting techniques (fire suppression and fire extinguishing) use technologically advanced firefighting equipment, which requires specific pressure and flow rates to ensure that they operate as designed. Too little or too much water can put firefighters safety at risk, as it may have an adverse impact on the environment that they are operating in e.g. too little water and a flashover may not be controlled; too much water and visibility may be severely impaired. TSI electromagnetic flowmeters are highly accurate across the whole range of firefighting flow rates and therefore ensure these situations do not occur.
Why are mechanical meters in water stream not such a good idea?
Fire pumps make the water stream very turbulent making accurate measurement using mechanical means nigh on impossible, Fire fighting water often contains debris which can damage the mechanical parts. The end result is at best inaccurate information, at worst case, a break down at any time e.g. mid incident.
Electromagnetic flow meters have no mechanical moving parts and nothing protruding into the water stream; the ideal technology for the fire service needs.
Electromagnetic flow meters
Paddle wheel flowmeters
98% accurate over a full range of fire fighting flow rates
Less accurate and a narrow measuring range
Highly reliable (no moving parts)
Subject to wear and tear, and susceptible to damage (moving parts in water stream)
Versatile. Can be installed anywhere on a fire fighting pump
Restricted locations due to turbulence impacting on accuracy. e.g. minimum of six pipe diameters needed after bend in pipe
GHOST READINGS *
Yes (paddles spin due to turbulence)
Comparison chart between electromagnetic and paddle wheel flow meters when used directly on the fire pump